825527-021 Armstrong Casing

The Armstrong 825527-021 Casing 4D 125# 4380 OS C/WR CI

Armstrong 825527-021 Casing – 4D 125# 4380 Cast Iron, OS C/WR

Overview

The Armstrong 825527-021 casing is a replacement pump casing built for Armstrong 4380 series pumps. It is a 4D design, rated at 125# pressure, constructed of rugged cast iron with oil seal (OS) and water return (C/WR) features. This casing ensures durability and reliability in boiler, heating, and hydronic pump systems.

Specifications

Features & Benefits

• Built to Armstrong OEM specifications for exact fit and performance

• 125# pressure rating supports demanding operating conditions

• Cast iron construction offers strength and durability

• OS / C/WR features help protect internal components and reduce leakage

• Ships same day in many cases – quick supply

Applications

• Hydronic heating systems using Armstrong 4380 series pumps

• Boiler feed, hot water circulation, and similar industrial pump systems

• Replacement of damaged or worn casings in Armstrong or compatible pumps

Installation & Maintenance Notes

• Ensure correct pump frame and size (“4D” type) when ordering replacement

• Inspect mating surfaces for flatness before installation

• Check seals, bolts, and fastening method to avoid vibration or misalignment

• Periodic inspection for corrosion or wear, especially in cast iron parts

Warranty & Compliance

• Covered under standard Armstrong part warranty when properly installed and maintained

• Meets Armstrong specification for 4380 casing parts

Related Products

• Other Armstrong casing variants (3D, 4E, etc.) with similar pressure ratings

• Full pump repairs including impellers, seals, adapters

• Accessories like casing bolts, gaskets, and water return fittings